Sheet-arresting mechanism for photographic apparatus



D. R. BISHOP May 20, 1958 SHEET-ARRESTING MECHANISM FOR PHOTOGRAPHICAPPARATUS Filed Dec. 29, 1953 2 Sheets-Sheet 1 ATTORNEYS May 20, 1958 D.R. BISHOP 2,835,177

SHEET-ARRESTING MECHANISM FOR PHOTOGRAPHIC APPARATUS Filed Dec. 29, 19532 Sheets-Sheet 2 g {NViNTZR BY United States Patent Oflice 2,835,177Patented May 20, 1 958 SHEET-ARRESTIN G MECHANISM FOR PHOTO- GRAPHICAPPARATUS Donald R. Bishop, Westwood, Mass, assignor to PolaroidCorporation, Cambridge, Mass, a corporation of Delaware ApplicationDecember 29, 1953, Serial No. 400,881

4 Claims. (Cl. 95--31) This invention relates to novel release means forconmember is mounted on resilient means so as to be movable in aplurality of directions and is normally urged into engagement with thesheet material and in a direction opposite the direction of movement ofthe latter. As the stop member becomes engaged by a portion of the sheetmaterial, it is moved forward therewith against the bias of theresilient mounting means until its movement and that of the sheetmaterial are arrested by means defining the limit of movement of thestop member. To permit continued predetermined advancement of the sheetmaterial, the stop member is moved in a direction substantially normalto the direction of movement of the sheet material out of engagementwith the engageable portion thereof. Upon withdrawal from engagementwith the sheet material, the stop member moves under the bias of itsmounting means in a direction opposite the direction of advancement ofthe sheet material. By virtue of this arrangement, only a momentarywithdrawal of the stop member is required to permit its return to aposition wherein it is adapted to engage the next successive engageableportion of the sheet material as it is advanced into alignment With thestop member. The release means may take the form of a push button or thelike for pivoting the means on which the stop member is mounted. Thistype of manually operative release means, while being essentiallysatisfactory, permits the operator to hold the button in operativeposition and thereby hold the stop member from engagement with thesheet. material while the latter is being advanced. When this occurs,

the sheet material will continue to advance without being arrested whenan engagement portion becomes aligned with a stop member.

It is accordingly an object of the present invention to provide, incombination with sheet-arresting mechanism having stop members adaptedto engage portions of sheet material during its advancement, novelrelease means for momentarily withdrawing said stop members fromengagement with said sheet material.

Another object of the present invention is to provide manually operativerelease means which are capable of effecting only a momentary withdrawalof said stop members from said sheet material.

The invention accordingly comprises the apparatus possessing theconstruction, combination of elements and arrangement of parts which areexemplified in the following detailed disclosure, and the scope of the.application of which will be indicated in the claims.

The sheet-arresting mechanism includes at For a fuller understanding ofthe nature and objects of the invention, reference should be had to thefollowing detailed description taken in connection with the accompanyingdrawings wherein:

Figure 1 is adiagrammatic, fragmentary, sectional view of portions ofthe camera of the self-developing type embodying the present invention;

Fig. 2 is a perspective view of an element of the sheetarrestingmechanism of Fig. 1;

Fig. 3 is a perspective view of the sheet-arresting mechanismillustrating its operation relative to a sheet material; and

Fig. 4 is an exploded perspective view of the herein disclosed manuallyoperable release means.

Generally, the herein disclosed invention is concerned with theprovision of a novel, manually operable release means in combinationwith mechanism for arresting the movement of sheet material. While thepresent invention is adapted for use in any type of apparatus whereinsheet material is advanced intermittently and mechanism is providedadapted to cooperate with portions of the sheet material for arrestingits advancement, it is particularly adapted for use in photographicapparatus and, for example, in cameras of the self-developing type nowwell known in the art. The invention is illustrated in the accompanyingdrawings as embodied in a photographic apparatus of the type generallyincluding means for processing exposed frames of a photosensitive sheet,by superposing said frames on areas of a second sheet and by spreadingathin layer of processing composition between said frames and areas.

A camera of the self-developing type embodying the herein disclosedinvention is illustrated in the accompanying drawings as having anexposure chamber and a processing chamber. Successive frames of aphotosensitive sheet may be successivelypositioned-within the exposurechamber wherein they are successively photoexposed. At the entrance tothe processing chamber there is provided a pair of pressure-applyingrollers adapted to receive therebetween the photo-sensitive sheet fromthe exposure chamber and to superpose and register the frames of saidsheet on areas of a second sheet. The second sheet has on one surfacethereof a succession of imagereceiving areas which are registrable withthe frames and has afiixed thereto a succession ofcontainers ofprocessing composition, one container being associated with oneimage-receiving area. When the sheets are advanced in superposedrelation between the pressure-applying rollers, processing compositionis ejected from a container and is spread in a thin layer between aframe of the photosensitive sheet and an image-receiving area of thesecond sheet, thereby forming a sandwich which is advanced into theprocessing chamber. By way of example, the

photosensitive sheet may include a silver halide layer and.

the second sheet include a silver precipitating layer. The processingliquid may include a developer, a silver halide solvent and analkali andis preferably quite viscous. When a layer of this processing liquid isspread between the photosensitive sheet and the second sheet, a latentimage in the photosensitive sheet is developed into silver and a silvercomplex is formed from undeveloped silver halide and transferred byimbibition to the second sheet where it is developed to produce a positive image.

A stop means is provided for arresting advancement of the sandwich whenone frame and the image-receiving area. with which it is registered haveadvanced entirely between the rollers. The aforementioned frame and areaare allowed to remain in the processing chamber for a predetermined.time during which the latent image in the frame is developed and apositive print is formed in the image-receiving area with which saidframe is registered. At the end of the predetermined processing time theprocessing chamber may be opened, the developed positive print removedand advancement of the sheets repeated.

Referring now to the drawings, wherein like numerals denote like parts,there is shown somewhat schematically in Fig. l a handheld camera of thefolding type which embodies the present invention. As a means forsupporting and enclosing the various components of the camera, there isprovided a housing generally indicated at 2t In the form shown, housingcomprises a front portion 22 which provides a central reentrant section24 having an exposure aperture 26'. Section 24 further provides guidetracks on opposite sides of the aperture which serve to position aportion 27 of a photosensitive sheet 32 for exposure in the focal planeof a lens. A suitable bellows 2% is provided, the bellows being securedto section 24. It is to be understood that suitable lens, shutter means,and erecting mechanisms (not shown) are provided.

A supply of photosensitive sheet material 32 is carried on a spool 34 ofconventional design and having a spindle around which sheet 32 is coiledand the spool is mounted within the housing adjacent one end of aperture26 on a pair of suitable shafts 36 extending from opposite ends thereofand pivotally secured in clip means A second sheet 4d, in conjunctionwith which photosensitive sheet 32 may be processed, is shown in Fig. las being supplied from a roll 42 mounted within the housing adjacent theother end of aperture 26. Sheet 4t) preferably comprises a suitable baseand a suitable image-receiving layer on one side of the base. Theimagereceiving layer, for example, may comprise one of the compositionsnow well known in the art which is adapted to receive, in successiveimage-receiving areas thereof, positive prints of the latent images inframes of photosensitive sheet 32. A succession of containers,designated generally at 44, are provided for carrying a liquidprocessing composition. As shown, containers 44 are fixed to theimage-receiving layer of sheet at substantially regularly spacedintervals from a location adjacent a leading end thereof toward thetrailing end thereof, containers 44 being so spaced that one containeris associated with one image-receiving area. Each container is providedwith a mouth facing toward the trailing end of sheet 40, which mouth isadapted to eject processing composition when opposed compressionalforces are applied to the container.

Means are provided defining a cylindrical chamber 43 within housing 20wherein roll 42 may be mounted. In the form shown, said means comprise apair of curved members 45 and 47, member 45 being secured to frontcasing portion 20 and member 47 being secured to rear portion 50.

Pressure-applying means are provided for processing latent images in theframes of sheet 32. In the form shown, the pressure-applying meanscomprise a pair of rollers 4-6 and 48 between which sheets 32 and 40 maybe advanced in superposed relation. Advancement of a frame of sheet 32and an associated image-receiving area of sheet 40 between the rollerscauses the ejection of processing composition from the mouth of acontainer 44 and spreading of the processing composition between theframe and the area to form a sandwich in which the latent image in theframe is processed and a positive print is formed in the area.

Means are provided for defining an exposure chamber wherein latentimages may be formed in frames of sheet 32 and a lighttight processingchamber into which a sandwich formed between rollers 46 and 48 may bestored for a predetermined processing time. Said means, in the formshown, comprise a rear portion 50 of housing 20. Viewing Fig. 1, rearportion 50 is pivotally attached to the lower extremity of front portion22 as by a hinge 54. An intermediate portion 52 is pivotally attached tothe upper extremity of front portion 22 by a hinge 56. Portions 50 and52, when in open position, provide access to the interior of the camera.When in closed position, portion 52 defines an exposure chamber inconjunction with front portion 22 and bellows 28. When in closedposition, portions 50 and 52 define, between and adjacent overlappingsurfaces, a processing chamber 58. Suitable latch means (not shown) areprovided for retaining rear portion 50 in closed position.

As a means for holding a portion of sheet 32 in position for exposure,there is provided a pressure plate mounted on intermediate portion 52 bysuch means as leaf springs (not shown).

In the illustrated embodiment, roller 46 is mounted on intermediateportion 52 and roller 48 is mounted on rear portion 50, the rollersbeing so arranged as to be operatively juxtaposed when portions 59 and52 are in closed position and to be spaced apart to permit sheets 32 and40 to be threaded therebetween when portions 50 and 52 are in openposition. In order to generate pressure between rollers 46 and 43, meansare provided for resiliently biasing roller 46 toward roller 48 whenportions 50 and 52 are in closed position. As shown, roller 4-6 ismounted on a pair of arms 62 which are pivotally secured to the oppositeedges of intermediate portion 52. Extending from opposite ends of roller46 are a pair of stub shafts 61 which are received in suitable bushings(not shown) in arms 62. By virtue of its mounting on pivotable arms,roller 46 is movable in a plane toward and away from roller 42 whenrollers 46 and 48 are operatively juxtaposed. The resilient biasingmeans in the illustrated embodiment comprises a pair of coil springs 64mounted in housing 2% and adapted to bear against enlarged sections 66of arms 62. it is to be noted that sections 66 of arms 62 function asguides preventing lateral movement of at least a portion of sheet 32which extends around roller 4-6.

In practice, sheet 32 extends from its spool past exposure aperture 26and into contact with roller 46. Sheet 40 extends from roll 4-2 intocontact'with roller 48 and into superposition with sheet 32 to formtherewith a sandwich which extends between the rollers and intoprocessing chamber 58. Rear and intermediate portions 50 and 52 are soconstructed as to provide, at the end of processing chamber 58 oppositerollers 46 and 43, an exit passage 68 through which portions of thesandwich positioned with the processing chamber may be removed. Anoperator, by grasping the leading portion of the sandwich extending fromthe passage 68, may draw the sandwich through the passage and therebyadvance unprocessed portions of sheets 32 and 40 between rollers 46 and48 into processing chamber 58. Thus, a frame of sheet 32 initiallypositioned for exposure in the focal plane of the lens adjacent exposureaperture 26 may be advanced toward registration within imagereceivingarea of sheet 40. Continued advancement of sheets 32 and 40 betweenrollers 46 and 48 causes ejection of processing composition fromcontainer 44 associated with the frame and area, and causes spreading ofthe processing composition between the frame and area to form a sandwichwhich advances into processing chamber 53. This sandwich is permitted toremain within processing chamber 58 for a predetermined period of time,during which the latent image in the frame is processed and a positiveimage is formed in the imagereceiving area of sheet 40.

it is considered desirable that light be excluded from processingchamber 53 during the processing of a frame and an image-receiving areapositioned therein. In accordance with the present invention means areprovided for rendering exit passage 68 lighttight. As shown, this meanscomprlses a cutter bar 79 pivotally secured by legs '72 to rear portion50 and having edge portions which, when bar 70 is in closed position,snugly contact portions of housing 20 that are adjacent to passage 63.

.-e,sas, 1 77 closed position. The edge 71 of bar 70 is normally in,contact with superposed sheer; 32 and 40 extending from qexit passage68 and serves as a cutting blade against which an operator can drawportions of thesandwich 1 extending through exit'passage68 for severingsaid portions from portions remaining within processing chamber 58.

Stop means are provided for arresting the movement of-thesandwich uponadvancement of a predetermined length thereof between rollers 46'and itin order to adapt it'for use in the illustrated embodiment, sheet 40is'provided with pairs vof regularly spaced perforations or openings 86,the openingsof each pair being in the opposite marginal portions ofsheet to and one pair being associated with one imagerreceiving area ofsheet 40.

The stop means include meansadapted to engage successive pairs ofperforations to arrest the advancement of sheets 32 and 40 atpredetermined positionsuduring their movement through the camera. :Inthe form shown, the stop means comprise a generally channel-shapedsupport member 76 at least equalin length-to thewidth of the sheets andhaving a baseportion 78 providing a surface in contact with which thesheets are adapted to move during advancement thereof. Base portion '78is provided with a pair of slots 88 so positioned that'opening 85 insheet 40 is adapted to move across base portion 78 in aligned relationtherewith. The stop means include a. curved end portion of member45forming an anvil 167 in contact with which the sheets are adaptedtoadvance.

Anvil 107 is provided with a pair of grooves, indicated at103, alignedwith slots 83 in base portion 78, said sheets being adapted to beadvanced between anvil 1127 and base portion '78. Member '76 includestwo side portionsSt) and. 32, side portion 82having a depending flange81 at .whichmember '76 is secured to rear casing portion 51 The stopmeans also includeiasubstantially fiat movable member9tl whichunderliesbase portion '76 of member 16. Movable member 90 is provided with a pairof cars 92 adapted to be engaged with suitably formed slots 94 in sideportion 330 of member '76, member 90 being pivotable with respect tomember 76 by virtue of ears92 which cooperate with slots 94 in sideportion 80 to act as'hinges. Member 90 is provided with a pair of slots96 in aligned relation with slots 88 in base portion '78. Means, to bemore fully described hereinafter, are secured to the medial portion ofmember 90 for pivoting or rocking the latter.

Apair of stop pins 100, which are aligned with grooves 108 and areadapted to engage a pair of apertures 86 in sheet 40, project throughapair of slots 88 in base portion 78 of support member "76 and a secondpair of slots 96 in pivotal member 90. Stop pins 100 are mounted ontheextremities of a spring-like detent member 98 formed of a suitableresilient material, for example spring steel or Phosphor'bronze. Detentmember 98 is adapted to mount pins 166 so that they are movable eithertogether or separately in a plane perpendicular to the sheets and, intheform shown, comprises a central section 102 a second section 110depending from said central section, and a pair of end sections 112extending from said second section 110 in substantially the plane ofsaid central section 102. Central section 1112 is provided with a hole104 formed therein through which means such as a rivet 106 may beinserted for rigidly securing section 102 to the mid portion of pivotalmember 90. By virtue of the construction of detent member 98, stop pins100 mounted thereon are movable longitudinally of slots 88 and 96,through which they project in a direction substantially parallel to thedirection of advancement of the sheets and are also movable into and outof the pairs of openings 86 in sheet ill in a direction substantiallynormal to the direction of movement of the sheets. Detent member 98 issecured at its central section 102 to pivotal member whereby pivoting ofthe latter results in the engagement of pins 100 with'a pair ofperforations 86 or their Withdrawal fromsaidperforations.

Resilient means are provided for'normally urging stop pins 100 intoengagementwith -a pair of openings 86 in sheet 469 with which theybecome aligned during the advancement of the sheets between anvil 107:and base portion 7'8. The resilient means comprises at least onecompression spring located between rear casing portion and pivotalmember 90 and, in the form shown, cornprise a coiled spring 114 engagedat its ends by rear casing portion filland the mid-section of pivotalmember 90. Stop pins 100 are urged by spring 114 toward the sheets andare so positioned with respect to slots 88 and 96 that they are movablein said slots against the bias of detent member 98 in the direction ofadvancement of the sheets.

Normally, the stop pins 100 are held in-contact with sheet 40 by theaction :of spring 114 so that they bear against or ride on the surfaceof said sheet as it advances between base portion "78 and anvil 107 ofmember 45. To permit pins 100 to extend completely through the sheets,anvil 107 is provided with grooves 108 aligned with the pins over whichthe perforations in the sheets advance. As a perforation 86becomesaligned with a pin 1%, the pin enters said perforation while thesheet-continues to advance in engagement with said pin for adistanceequal to the length of slots 88 and 96 through which the pin projects.The pins are carried forward by the sheets in the direction ofadvancement of the latter-to the limits of slots 88and 96 Where theirmovement, as well as that of the sheet, is arrested by'said limits. Aspins lilo are carried forward, detent member 98, and particularly thesecond sections 110 thereof, is deformed or deflected, thereby providinga bias on pins 1'90 in a direction opposite the direction ofmovement of the sheets.

Means are provided for withdrawing stop pins 103 from engagement with apair of perforations 86 in sheet 40 to permit the further advancement ofthe sheets through their exposure and processing cycles. In the formshown, the aforesaid stop pin withdrawal means comprises a lever 116having a substantially flat end section'118 at which it is secured bysuch means asrivet 106 to the midportion of pivotal member 90. Lever 116includes an arm section 120 having a first portion 128a extending'angularly upward (as viewed in Fig. 4) from end section 118 to an apex121 and a second portion 12Gb bent downwards fromapex 121 of arm section120 and curved upward at its end 122. Arm section 120 may be providedwith a groove or rib 124 formed therein for added strength and rigidityat its apex 121. To providea rigid structure and prevent bending oflever 116 at the point where end section 118 and arm section 120 join,the lever is provided with a pair of lateral side or flange portions 125extending between said end section 118 and the first portion 12% of armsection 120. Withdrawal of stop pins 100 from engagement with a pair ofperforations 86 in sheet 46 is effected by pivoting lever 116 andpivotal member '96 secured thereto. Upon Withdrawal from engagement withperforations 86, stop pins 100 move under the bias of second sections110 of detent member 98 in a direction opposite the direction ofmovement of the sheets to the limits of slots 88 and 96 and are retainedthereat in engagement with the surface of sheet 40 until advancement ofsaid sheet results in the alignment of another pair of perforations 86with pins 100. While the sheets have been illustrated as being providedwith pairs of apertures or perforations adapted to be engaged by pins,it is to be understood that the sheets may also be providedwith marginalnotches, hooks, or raised sections adapted to be engaged by suitablestop members.

in accordance with the present invention, manually operable means areprovided for momentarily pivoting lever 116 so as to withdrawstop pins100 from engagement with openings 36 in sheet 40. In the form shown,said means comprise an actuating lever 126 and a retainer plate 128.Actuating lever 126 includes a curved central portion 130 and two endportions 132 and 134 extending, respectively, upward and downward (Fig.4) from said central portion 131 Lever 126 is adapted to be retained ina recess, generally indicated at 136, formed in the rear portion 50 ofthe camera housing with end portion 132 extending through an opening 138in said housing. End portion 132 may be serrated or grooved and ismanually en ageable for pivoting lever 126. The central portion 130 oflever 126 is substantially wider than end portions 132 and 134 andincludes a round hole 14% extending from side to side thereof andadapted to receive an elongated shaft or pin 142, a curved upper surface144, and a circular lower surface 146, the center of curvature of saidlower surface 146 being the axis of hole 140. Pivot uin 146 projectsfrom opposite sides of said central portion 130 and is received insuitably formed recesses in rear portion 51) of the camera housing forpivotally mounting lever 126. To retain lever 126 in its operativepivotal position within recess 136 in the housing with end portion 132projecting through opening 138, retainer plate 128 is substantiallyrectangular, having a recess or circular depression 148 formed thereinand adapted to receive central portion 13b of lever 126, said depression148 having an upper surface conforming to the lower surface of centralportion 130. Retainer 128 includes an opening 15% in depression 148through which lower end portion 134 of lever 126 is adapted to extend,and holes 152 at its corners through which means such as screws orrivets 154 may be inserted to secure retainer 123 within recess 136.When assembled, the actuating lever 126 is pivotable about pin 142 andis retained in operative position by pin 142 and central portion 130which is retained in depression 148 of retainer plate 128.

A further feature of the present invention resides in the provision ofmeans adapted to permit only the momentary or instantaneous pivoting oflever 116 and member 9% whereby stop pins 100 are Withdrawn fromperforations 86 in sheet 40. Immediately upon Withdrawal of pins 1% fromperforations 86, the pins are again urged into contact with sheet 40 andpositioned to engage the next successive pair of perforations as theyare advanced into alignment with the pins. It is apparent that by thismeans the pins cannot be withdrawn from contact with sheet 41) while thesheet is advanced and that as a pair of perforations 86 in sheet 40 areadvanced into alignment with said pins, said perforations mustnecessarily engage the pins, thereby arresting the advancement of thesheets. Pivoting of release lever 116 is effected by the action of endportion 134 of actuating lever 126 as it is pivoted by the operator, Endportion 134 is adapted normally to contact arm section 120 of lever 116at a point on said arm section 121) adjacent either of its ends and isillustrated (in Fig. 1) as contacting arm section 12% adjacent its end122. As actuating lever 126 is pivoted, end portions 134 moves towardthe apex 121 of arm section 129 as it rides on and bears against eitherfirst portion 1249a or second portion 120b, thereby deflecting orpivoting lever 116. At the instant when end portion 134- of lever 126rides over the apex 121 of arm section 126, the pivotal movement oflever 116 is a maximum and stop pins iilfi are withdrawn from engagementwith perforations 86 in sheet 40. The end of portion 134 of lever 126 isrounded, making it substantially impossible to hold lever 126 at apex121 of arm portion 121) and thereby hold pins 101) out of engagementwith sheet 49. Thus, by a single pivotal movement of the actuating lever126, the stop pins are withdrawn from engagement with the sheets andadvancement of the latter is permitted. The foregoing construction andarrangement of elements has obviated the possibility of the stop pins101) being held out of engagement with sheet 40 by the operator so thatsaid stop pins do not engage successive pairs of perforations 86 andpermit the uninterrupted advancement of the sheets through the camera.

Since certain changes may be made in the above apparatus withoutdeparting from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. In photographic apparatus, means for arresting the movement of sheetmaterial through said apparatus, said means including at least one stopmember for engaging successive engageable portions of said sheetmaterial to arrest its movement, resilient means for mounting said stopmember for movement in a plurality of directions and for urging saidstop member into contact with said sheet material and in a directionsubstantially opposite the direction of advancement of said sheetmaterial, said stop member being displaceable in the direction ofmovement of said sheet material upon being engaged by one of saidengageable portions of said sheet material, pivotal means for limitingthe displacement of said stop member in the direction of advancement ofsaid sheet material to arrest the movement of said sheet material andfor moving said stop member in a direction substantially normal to thedirection of advancement of said sheet material to withdraw said stopmember from engagement with said sheet material and permit the displacedstop member to return under the bias of said resilient means to itsnormal position prior to displacement, said stop member in its normalposition being in contact with said sheet material in readiness to beengaged by the next successive engageable portion of said sheet materialas the latter is advanced into alignment with said stop member, andcontrol means for causing said pivotal means to only momentarilywithdraw said stop member from engagement with said sheet material, saidcontrol means comprising a manually engageable lever having an endportion extending exteriorly of said apparatus, a central portion atwhich it is mounted for limited pivotal movement within said apparatusand an actuating portion having a curved end section movable in anarcuate path, said pivotal means including a generally V-shaped sectionhaving a curved apex located in the arcuate path of said curved endsection or said actuating portion for coacting with said curved endsection during arcuate movement thereof in either direction formomentarily pivoting the last-mentioned means so as to move said stopmember against the bias of said resilient means from engagement withsaid sheet material.

2. In photographic apparatus, means for arresting the movement of sheetmaterial through said apparatus, said means including a pair of stopmembers for engaging successive pairs of perforations in said sheetmaterial to arrest its movement, resilient means for mounting said stopmembers for movement independent of one another in a plurality ofdirections and for urging said stop members into contact with said sheetmaterial in a direction substantially perpendicular to its direction ofmovement and in a direction substantially opposite the direction ofmovement of. said sheet material, each of said stop members beingdisplaceable in the direction of movement of said sheet material uponengagement by one of said perforations, pivotal means positioned betweensaid resilient means and said sheet material, said pivotal meansincluding means for limiting the displacement of each of said stopmembers in the direction of movement of said sheet material so as toarrest its movement and means for moving said stop members in adirection substantially perpendicular to the direction of movement ofsaid sheet material to withdraw said stop members from engagement withsaid perforations and permit the displaced stop members to return underthe bias of said resilient means to their normal position prior todisplacement, said stop members in said normal position being in contactwith said sheet material in readiness to be engaged by the next pair ofperforations as the latter move into alignment with said stop members,and control means cooperating with said pivotal means for onlymomentarily with drawing said stop members from engagement with saidsheet material, said control means comprising a manually engageablelever having an end portion extending eXteriorly of said apparatus, acentral portion at which it is mounted for limited pivotal movementwithin said apparatus and an actuating portion having a curved endsection movable in an arcuate path, said pivotal means including agenerally V-shaped section having a curved apex located in said arcuatepath of movement of said curved end section of said actuating portionfor coacting with said curved end section during arcuate movementthereof in either direction to momentarily pivot the last-mentionedmeans so as to move it against the bias of said resilent means andwithdraw said stop members from engagement with said sheet material.

3. In photographic apparatus, means for arresting the movement of sheetmaterial through said apparatus, said means including at least one stopmember for engaging successive engageable portions of said sheetmaterial to arrest its movement, resilient means for mounting said stopmember in contact with said sheet ma terial and for limited movement ina plurality of directions so that said stop member is displaceable fromits normal position in the direction of movement of said sheet materialupon engagement with an engageablc portion thereof, said resilient meansso mounting said stop member as to return the latter to its normalposition upon the momentary disengagement of said stop member from saidengageable portion, control means for only momentarily withdrawing saidstop member from engagement with said sheet material, said control meanscomprising a lever having an end portion extending exteriorly of saidapparatus, a central portion at which said lever is mounted for limitedpivotal movement within said apparatus and an actuating portion having acurved end section movable in an arcuate path when said lever ispivoted, pivotal means for moving said stop member from engagement withsaid sheet material in a direction substantially normal to the directionof movement of said sheet material, said resilient means cooperatingwith said pivotal means for normally urging said stop member intocontact with said sheet material, said pivotal means having a portionbent at an obtuse angle with its apex positioned in said arcuate path ofmovement of said curved end section of said actuating portion, saidcurved end section of said actuat ing portion being capable, duringpivotal movement in either direction, of coacting with said angularportion to cause a momentary deflection of said angular portion of saidpivotal means and thereby pivot the latter, pivotal movement of saidpivotal means being ettective to momentarily withdraw said stop memberfrom engagement with said sheet material at the instant said curved endsection of said lever is in coaction with said apex of said angularportion.

4. In photographic apparatus, means for arresting the movement of sheetmaterial through said apparatus, said means including a pair of stoppins for engaging successive pairs of perforations in said sheetmaterial to arrest its movement, resilient means for mounting said stoppins for limited movement independent of one another in a plurality ofdirections so that each stop pin is displaceable from its normalposition in the direction of advancement of said sheet material uponengagement with one of said pair of perforations, the momentarydisengagement of a displaced stop pin from said perforation permittingsaid stop pin to return under the bias of said resilient means to itsnormal position in preparation for engagement by one of the next pair ofperforations in said sheet material as said perforation is advanced intoalignment with said pin, and control means for only momentarilywithdrawing said stop pins from engagement with said sheet material,said control means comprising a lever having a manually engageable endportion extending exteriorly of said apparatus, a central portion atwhich said lever is mounted for limited pivotal movement Within saidapparatus and an actuating portion having a curved end movable in anarcuate path, pivotal means for effecting the movement of said stop pinsfrom engagement with said sheet material in a direction substantiallyperpendicular to the direction of movement of said sheet material, saidresilient means cooperating with said pivotal means for normally urgingsaid stop pins into contact with said sheet material, said pivotal meanshaving a base portion at which it is pivotally mounted, said baseportion being positioned between said resilient means and said sheetmaterial and having a pair of slots through which said pins project andadapted to limit the displacement of said pins, and an angular armportion extending from said base portion, said arm portion being bent atan obtuse angle intermediate its ends with the apex of said angular armportion located in said arcuate path of movement of said actuatingportion, said curved end of said actuating portion being so formed as tocoact with said arm portion during pivotal movement of said lever ineither direction to deflect said arm portion and momentarily pivot saidpivotal means against the bias of said resilient means only when saidcurved end of said actuating portion is in coaction with said apex formomentarily withdrawing said displaced stop pins from contact with saidsheetmaterial to permit the return movement of said stop pins to theirnormal position.

References Cited in the file of this patent UNITED STATES PATENTS1,183,215 MacDonald May 16, 1916 1,307,386 Waite June 24, 1919 1,535,930MacDonald Apr. 28, 1925 1,740,279 Bornmann Dec. 17, 1929 1,828,205Schmitt et a1. Oct. 20, 1931 1,959,922 Maspons May 22, 1934 2,543,159Fairbank Feb. 27, 1951

